Add RotatedPole projection

For LAM grids, the original implementation gives the choice to interpolate icosahedral ICON data onto a regular lonlat grid. For this, corner points can be chosen via lon_reg, lat_reg when generating a new ckdtree. However, the cropping via corner points is not very well suiting the rotated EURO-Cordex grid. Therefore, an adaptation has been made using the new function ckdtree_hgrid_rotated. The lon/lat coordinates (given as lon(rlon,rlat) and lat(rlon,rlat) in the clm-grid europe011_rotated_grid.nc) can be provided as 2D fields to this function (Lon=..., Lat=...). Additionally, the rotated coordinates (rlon and rlat in the clm-example) and the coordinates of the rotated pole have to be provided (rlon=..., rlat=..., pol_lon=..., pol_lat=...) as they are needed for the correct plotting.

For plotting, xlim and ylim have to be set in the Ddict_global (pyicon/quickplots/qp_driver.sh) or directly in the call of hplot_base.

Important settings to activate the plotting on the rotated grid can be done in qp_driver.py (or in the config file):

rgrid_name_atm = 'regional_0.25_europe011_rotated'```
projection     = 'RotatedPole'